To: "Multiple recipients of list TVROSAT"
From: Gary Bourgois
Subject: Toy Report: CDM-800 Video Standards Convertor
Date: Tuesday, January 9, 1996 16:24:34 EST
You have possibly read the review by David Hawkins of the CDM-600 video
standards convertor. In his review he stated that he wished that Global
Communications would offer a convertor with higher sampling. The CDM-800 is
just such a unit. Admittedly the cost is higher than the hobby style
CDM-600, but the model 800 is a more professional style unit.
When I unpacked the device, I was impressed with the construction quality.
While it is small in size, the cabinet is a metal one, and very sturdy. This
unit will automatically detect the line voltage, and works on a wide range of
available mains power, and even comes with a handy conversion power plug for
use in various other countries.
Connecting the unit is simple, and operating it requires pushing only one
button.
I hooked mine up to the output of my Drake 1824, and from the CDM-800 video
feeds to a video distribution amplifier, and into my UHF modulator system, as
well as video production switcher (The Videonics MX1, see separate review).
The Drake also has a dedicated VCR fed from the Distribution Amp. There are
connections for both stereo audio and video.
Unlike the CDM-600, which has autodetect of video standard, the CDM-800 does
require you set switches to determine what your input and output standards
are. In practice this is no big deal, since I have never run into a SECAM
signal, though if you can see to the Russian Satellites, and they are
transmitting in SECAM (I am not sure if they still use SECAM or if they have
converted to PAL for uplinking) you will have to select for SECAM by a slide
switch at the back of the unit. The input and output standards are switch
selected. It does NTSC 3.58, or NTSC 4.43. For use here in the USA, just
leave your output on N3, which means NTSC 3.58. Set the input to P for Pal,
and with all cables connected, place the unit in it's permanent location.
The connection took only a couple minutes, and I was off looking for
something to CONVERT!
The first signal I went for was TDF1, the French Channel on Intelsat 601,
transponder 3. I had the CDM-600 set in BYPASS mode, where the signal just
goes straight through with no processing. As always, I was presented with a
Rolling black and white image. When I pressed the bypass mode off to engage
the processing, the image instantly locked up in full color. One problem,
the picture was upside down. This is not the fault of the CDM-600, this is
the scrambling system used by TDF-1. Well, no problem, says I, and I punched
up the Drake on the MX-1 and went to INPUT FX, and flipped the picture and
VOILA as they say at TDF-1, the image was in proper perspective, except for a
part at the bottom of the screen, which is NOT reversed for some reason.
Still the image (A quiz show) was perfectly visible, and to my surprise, the
channel was not nearly as noisy as I thought it would be. There were
actually no sparklies, though the image was not perfect, having a bit of
grunge to it. Chroma seemed a little hot, but otherwise the color
reproduction was faithful, and grey scale quite good.... Definately not bad
for an 8 bit system. I looked carefully for motion artifacts, and noted that
the algorithm being used for the 50 to 60 frame rate is not really all that
bad. Actually far better than that which was used years ago when these units
cost $20,000 and were the size of a small refrigerator. There was none of
the repetitive jerking on continuous motion, though you do see an occasional
interpolation.
I then went over to Orion to check out ASIANET the other 24 hour PAL signal
over the Atlantic. Since I am past the edge of their beam, this image is not
quite as good as the TDF-1 signal. This gave me a chance to see what the
CDM-800 does with a less than perfect PAL input signal.
The image was quite viewable, but here I did find some artifacts present.
There was some chroma lag for some reason, and every now and then there would
be a green scanline in the image. I mark this off to the instability of the
received signal. Still even with these imperfections, the video was still
quite watchable. The program was the usual Indian Musical Love Story. I can
watch these only for a while, as it always seems I have seen the movie
before.
These two signals were the only ones up on the air this afternoon, but I am
all set now when a newsfeed or other program pops up on the Atlantic
satellites, or domestic birds. While I have two Multistandard video
monitors, the problem I have always had was taping PAL material. I used the
poor man's standards convertor, pointing a camera at the PAL screen, and
putting up with flicker. For the past few years, I did manage to cut the
flicker down, as I have a mode on my JVC camera which integrates several
frames (used for low light conditions) so I got a jerky picture instead of a
flickery one. Now I am able to make standard NTSC recordings from PAL
originals, so I am a happy camper.
At $529, the CDM-800 is almost $200 more than it's smaller brother, and for
most hobby applications it is probably overkill. Since I plan to also do PAL
and NTSC videotape conversions, I wanted the better unit.
Here are some specs:
INPUT TV SYSTEMS NTSC, PAL, SECAM
OUTPUT TV SYSTEMS NTSC 3.58, NTSC 4.43, SECAM
CONNECTION TERMINALS VIDEO INPUTS: 2
VIDEO OUTPUTS: 2
AUDIO INPUTS (L+R) 2
AUDIO OUTPUTS (L+R) 2
SAMPLING FREQUENCY Y: 14.318 MHz
R-Y: 7.159 MHz
B-Y: 7.159 MHz
DIGITAL CORD BIT Y: 8 BITS
R-Y: 8 BITS
B-Y 8 BITS
LINE CONVERSION: 525 625 LINES
FIELD CONVERSION: 60 50 FIELDS
AC VOLTAGE: 110V/220 50/60 Hz
DIMENSIONS W: 280mm H: 45mm D: 230mm
WEIGHT: 3.2 kg
ACCESSORY: ONE SET OF VIDEO/AUDIO CONNECTING CABLE
FIELD MEMORY: 4M
STATIC RESOLUTION: 500 LINES
DYNAMIC RESOLUTION: 300 LINES
BUILT IN TIME BASE CORRECTION (TBC)
TWO INPUTS/TWO OUTPUTS
Available from:
Global Communications 608 546 2523
P.O.B. 747
Spring Green WI 53588
Note, I do not work for Global Communications. My affiliation is that of a
very happy Global Customer with a TON of sat toys I bought from them. Mike
and Laurel are always looking for new specialty gizmos for the DISH HEAD, and
these PAL to NTSC convertors are just the thing for the international sky
scanner.
--
/ Gary Bourgois, WB8EOH, The Birdwatcher: Marquette Michigan USA \
([-o Keeper of The r.v.s.t. FAQ, Wildfeeds List, and Radio Guides o-])
\ flash@lopez.marquette.mi.us REALAUDIO SITE AT: http://ttn.nai.net/ /
Friday Night Live E2/18 5.8 SOON Voicemail/FAX: (906) 228-7477